A Conference on the "Delayed Consequences of Cancer Therapy: Proven and Potential" has been scheduled by request of the Cancer Clinical Investigations Review Committee (CCIRC). Cancer treatments all have their deleterious consequences. Those associated with surgery are well-known; the damage produced by chemotherapy and radiation therapy is becoming better understood. Many of the deleterious effects are long-delayed, and are seen only years after delivery of therapy. As cancer management becomes more successful, and there are more long-term survivors of treatment, the late consequences of successful treatment become increasingly important. The Conference is designed to explore our current knowledge of the deleterious consequences of treatment, and to make estimates for what might be expected in the future. Both the childhood and adult age groups are to be discussed.